This invention relates generally to multitasking controllers comprising a microprocessor for treating, by time-sharing, a plurality of tasks each comprising a series of instructions, task storage means, such as a ROM, for storing a number of said tasks, and data storage means, such as a RAM, for storing variable data created and used by said microprocessor. The multitasking controller is suitable for use in horological applications, and it will be convenient to hereinafter disclose the invention in relation to that exemplary application. It is to be appreciated, however, that the invention is not limited to that application.